When base drive circuits such as the one described in copending application Ser. No. (481,695) are used, base drive circuit controllers are needed to provide the appropriate control waveforms.
A problem that occurs in providing properly timed waveform signals to base drive circuits for two series-connected power switching devices, is that the high currents being switched by the power switching devices, generate voltage transients which can couple to the base drive circuit controller circuit and be misinterpreted as signals from the system controller. The system controller generates signals indicative of the desired conduction of the upper or lower power switching device based on a predetermined modulation scheme.
Another drawback of conventional base drive circuit controllers is that they employ analog timing circuits which frequently require adjustment and require components which are adjustable.
Accordingly, it is an object of the present invention to provide a base drive circuit controller that is immune to false triggering during waveform timing sequences.
It is a further object of the present invention to provide a base drive circuit controller which does not use analog timing circuits.
It is a still further object to provide a digital base drive controller that can be integrated on a single chip.